He's a bit of a prig
Summary : So when Jack Frost, yes, the Spirit of Winter Jack Frost, heard there's a hidden society using his name, well... he was super flattered.
Jack have been spending his life having fun trips across the world. One day he stumbled upon a house and witnessed a man killing a Father, Mother, Sister and Brother.
It was a normal thing for him after passing by the World Wars, but he grew interested when someone stated his name through a speaker call, Jack Frost. Jack had been steadily spreading his created legend as Jack Frost for the last two centuries so he was surprised to hear a human with the same name.
After that day, he spent his time tagging along with the killer and was super flattered at the 'Jacks of All Trades' brotherhood society, even if there were only five human Jacks. He loves to mess with their killings and odd jobs, disturbing their dysfunctional 'family' meetings, their private lives, sometimes their sex lives if he was feeling vindictive.
Bunnymund, the Spirit of Spring and the Easter Bunny, mistook him to be hanging out with child killers and went out of his way to be spiteful. Jack was offended, because he loved the children and he was actually making the human Jacks assassinations harder, but to be honest, he really wasn't helping his own case by still hanging out with the Jacks society. It was a technicality that the two spirits ignored.
Toothiana Fey, the Spirit of Summer and the Tooth Fairy, holds a crush on his handsome looks (let's be honest it's his amazing teeth). Jack was aware (oh, he's very aware), but he didn't do anything with it. She wasn't his type, too girly. Aside from that, she was strangely wary of him. She likes to think she tolerates his choice of companions but she wasn't sure if she won't do anything rash, like, maybe judging him. It didn't help that Jack flirts her at unexpected times and leaving her flustered every time!
Nicholas St. North, Spirit of Autumn and the Santa Claus (don't ask how that works it just does), always tries to rope him to take on his responsibilities more seriously but Jack never really heeds his advice. The man was either jolly or bossy and Jack doesn't deal with bipolars (which is sad and really funny considering he and the other Jacks are bipolars).
Sanderson Mansnoozie, Guardian of Earth and the Sandman, was on friendly terms with Jack. They would have been the best of best friends if only Sandy wasn't so busy every hour every single f* day and doesn't speak as if he was reading a bedtime story. Poor Jack he was a sucker for those and always ended up asleep when Sandy actually talks to him.
So, he has a brotherhood of his own name running around exploiting and murdering people for their idea of fun and his season "siblings" aren't chummy with him. Though the five human Jacks ended up in Hell, at least it was an interesting adventure for his 297th birth day.
AN: "A man named Jack-" and I immediately jumped around my bed thinking Jack Frost! Jack Frost! Jack Frost! and quickly read through the Graveyard Book. It was so exciting and I smiled so wide at the Harry Potter reference (Sleer's snake at the beginning of the story) and thinking Oh Kaneki Ken! when guessing what the fuck is Silas supposed to be and I screamed when I read about Mr. Frost—Damn it I knew he must be the nasty killer I was right fucking shit this book is great JACK FROST JACK FROST JACK FROST—point is I was really crazy. Had an internal fangasm for five minutes and wrote this in 10 minutes give or take.
Feel free to adopt the plot or something. I just spit this one-shot out of randomness.